Thread case retaining device for sewing machines



July 10, 1945. A. sfcLARK THREAD CASE RETAINING DEVICE FOR SEWINGMACHINES Filed April 11, 1944 Patented July 10, 1945 itanananossanammmenavioc FOR SEWIN e memes;

' Alfred s. Clark, Bealy; Mass, mam us United I Shoe MachineryCorporation, Flemington, N. 1., acorporation of. New Jersey v j 5Application April 11, 1944, serial No. 530,497

Maclai s. (cilia-196 The present invention relates to bobbin or lockingthread ease retainingsdevices for lockstitch sewing machihesof the typein which the thread case is mounted foreasy removal from within a rotaryloop taker or shuttle tor-carrying loops of needle threadabontthej-thread case. l r

r "In this type of sewing machine,'the threadcase is removed fromthemachine for replenishment of the supply of lockingthread and replacedafter a newsupply has been inserted. To 'holdjthe thread case inposition and to prevent it from I'D-1 engaging means i is provided inthe dorm of l a swinging .meteiiner pivotally supported on the frame ofthe machine 'for movement, toward and from the thread case; In themachine disclosed in United States Letters Patent No; 473,870,

'talting with the loop taker, suitable thread case granted April26,..1892, :upon an applicationfiled in the names ofzaehary T. Frenchand William C. Meyer, the parts are 'so arranged that it ispossibie tohold the thread tease manually in position while swinging theretainertoward and from thethread case. When the retainer forms-apart or a coveror door fora protecting case such as is disclosedin UnitedstatesvllettersPatent No. 1,302,597,:grahted May :6, 1919;111:011anapplicationof Thomas H. Seely; it is-impossible to hold the threadcasein position manually while swingmg the cover toward and from thethread case. Machines of this type are intendedto he operated with waxedthread the wax from the thread frequently causing the thread case toadhere to the retainer sothat, when the retainer is swung open, thethread case comes withit, falling to the floor and becominginconvenience.

damaged or resulting in In United States Letters Patent No. 1,471,930,

granted October 23, 1923, upon an application filed in the name ofWilliam G. Trohon, a length of resilient wire is bent with a number ofcoils and a curved substantially horizontal arm of the wire extendsacross the front of the thread case between the thread case and theretainer. With such a resilient arm, the thread case is held in placewhen the retainer is swung open and at the same time the thread case maybe removed manually merely by flexing the wire to one side. Theformation of coils in the wire to provide the necessary amount ofyielding movement for easy flexure of the wire while removing the threadcase, however, is detrimetal to the strength of the wire and the arm ofwire which extends across the front of the thread case is solocated thata loop of thread being carried by the shuttle about the thread case may,under some circummg conditions, frequent replacement may essary.

stances, become impaled on the wire. Asa result,the wire is flexedviolently while the impaled loop of thread is being contractedtoward thework. Such flexure may weaken the wire further or change its shape,particularly along those parts Within the coils so that, underordinaryoperatpeace The objects of the present invention are to avoidthe diiiiculties above enumerated and to provide simplified and improvedmeans for preventing 1 displacement of the locking thread in alockstitch shoe sewing machine of meme referred to even thoughthethreadcase retainer is swung to openposition er the machine is-op-'erated through a few sewing cycles without-cu gagement oi the retainerwith the thread fease.

The principal features of the invention according'ly reside in a sewingmachine or the type a efer-red to provided with a hook needlega look--ing thread case mounted for easy removal the machine and a loop takerfor carrying loops of needle thread about the locking thread case inwlhichthere are provided means for preventmg dis-placement of the threadcase comprising a spring arm extending across the exposeds'ideofthe'l-oop talcerwith-one end bent across the side of the thread case inthe direction of movement of the thread in the needle loop while theloop is being carried by the looptaker about the thread case.-

The loop taker. of the machine in which this feature of the invention isembodied is constructed in aconventional manner with a needle loopentering beak'at the root of which is: formed a throat arranged to carryeach loop of needle thread in a circular path about the locking threadcase. In the illustrated form of the invention, the horizontal arm ofthe displacement preventer extends across the loop taker outside thecircular path of thethroat so that there is no possibility of a needleloop becoming impaled while being carried about the threadcase.

These and other features of the invention will be clearly understoodfrom the following description; the appended claims, and theaccompanying drawing in which Fig. 1 is a view in front elevation of aportion of a shoe sewing machine embodying the invention Fig. 2 is aplan view of the loop taker, thread case and thread case retainertogether with means for preventing displacement of the thread caseillustrated in Fig. 1; and

Fig. is a detail perspective View of the improved displacementpreventer.

The machine illustrated in the drawing except ashereinafter described isthe same as that disclosed in the patents above referred to and isprovided with a loop taker in the form of a shuttle H) which isrotatably oscillated in a shuttle race l2 at the front bathe machine;"I'hel shuttle r'ace] constitutesa part of a'casing 14 secured by a boltIE to a lug l8 on the machine frame. The

locking thread is contained in a thread case 20' wire aside orWithdrawing the thread case forwhich is easily removable from-acylindrical re 'cess in the front of the shuttle, it being retained inthe recess and prevented from oscillation with the shuttle by means ofasw'ing in'g'; retainer 22,] in the form of a heat retaining caseorhoo'd, more fully illustrated and described in the Seely pat ent. I i

The means for preventing displacement locking thread case while swingingthe retainer taohment with the machine frame and the ex:

treme end ofthe armfina manner to reduce the strength of the wire or toformirregularities upon Whichthread; or foreignmaterial may becomeentangled. At the extreme free end'21, the hori zontal armor thedisplacement preventer is bent throl h a graduallcurvature ofrelativelylarge radius order toextend downwardly across a side of the thread casein the direction of movement of a loop of eedle'thre ad- .being carriedabout the, thread case by the looper. A portion of the thread inthelneedle loop is indicated at 28. -It is. evident that, as, theshuttle which is formed with abeakifl picks up each loop of thread, thethread will slide toward a throat 32 i formed' atflthe, root of the beakandv be carried within the throat.aboutqthe thread case through a circula i a d b he ts a hrl 34;:lTh? hQI'iZ ntaI armifi f the wire is locateda substantial distarioeaboveand outside the path 34 taken by the throatof the'shuttle, and the only possible; engagement of the thread in theneedle loop with the wire is atits extreme downwardly extending end 21.Since this end i bent in the direction in which the needle loop movesduring normal sewing operations, there is no chance for the loop tobecome impaled on the end of the Wire.

In removing the thread case from the machine, the retainer 22 is opened,and there is suflicieht flexibility in ,tl'ier hdri'zontai ,arm 26 ofthdisplaceinent prevehterto enable removal of the thread case either bybrushing the preventer wardly until it clears the shuttle and thenmoving the; thread case laterally. The absence of small radius coil inthe preventer not only avoids the'possibility of weakening the wirewhich, dur- 'fing its m'anufacture'is subject to a high degree oftensile strength and brittleness by drawing,

but. also; eliminates several steps in the manufacture of the preventer.Thus, the expense of manufacture is reduced and a device of greaterdurability results. 1 a r a J The nature and scope, ofythe inventionhaving beenflindicated and a machine embodying ,the' several features intheir preferred form having specifically been describBCL What is claimedis: i 1

1. A- sewing machine having stitch forming devices,lincluding' a lockingthread case mounted for easy removal from the, machine, and a loop takerfor carrying loops of needle thread about the locking thread case, and:means for prevent-, ing displacement of the thread case comprising aspringarm; extending across, the ,loop taker with one ,end bent across,a side ofthe thread case in, the direction of;.,the movement of a loopof, needle thread while being carried by the loop:

taker aboutthe thread case. A v

2.;A sewing machine having stitch forming devices, including a; lockingthread case mounted for easy removal from the machine, and. aloop taker,provided witha needle loop entering beak at the root of'whichis formed.a, thread engaging throat, arranged to carr'y, .-each loop of. needlethread in a circularpathabout thelocking thread case, and meansforpreventing displacement of the thread case comprising a spring armextend-- ing outside the circular path of the loopqtaker throat with itsthread case engaging nd inside said circular path bent across a side ofthe thread casein the, direction-of movement of the thread in the needle:loop,;while-, being carried by the loop taker about the thread. case. ia .i

Ens-CLARK

